For manufacturing plastic W/O emulsion spreads, e.g. margarine, a margarine fat should be used having a well balanced ratio of liquid and solid fats throughout the entire area of use temperatures which usually is from 5.degree. C. to about 20.degree. C.
Historically attempts were made to meet this aim by using blends of natural fats having a sufficient solids content, resulting however in products of unsatisfactory spreadability, consistency and mouthfeel. The use of mixtures of fats hardened to different degrees of saturation is another approach, but for nutritional reasons in recent years the desire is expressed that the level of saturated fatty acids (SAFA) of the component triacyl glycerides of the fats should be kept as low as possible.
W/O emulsion spreads have, been on the market for some time aiming to meet this need. Typically, the margarine fat of these products consists of about 87% liquid oil, e.g. sunflower oil and 13% of a hardstock consisting of a randomly interesterified mixture of fully hardened lauric fat, e.g. fully hardened palmkernel oil, and fully hardened palm oil.
In order to allow the use of even less hardstock in the margarine fat, EP 89,082 recommended H.sub.2 M rich hardstocks. The preferred method described in EP 89,082 for producing such hardstock is randomly interesterifying a partly or fully hydrogenated lauric fat having a melting point |ranging from 30 to 41.degree. C., with a fat, which can be fully or partly hydrogenated, fractionated or non-fractionated, wherein at least 60% of the fatty acid residues are C.sub.16 - or C.sub.18 -fatty acid residues. This C.sub.16 -C.sub.18 fat is preferably selected from palmfat, soybean oil, groundnut oil, sunflower oil, maize oil, rapeseed oil, having a melting point ranging from 50 to 71.degree. C.; and fractionating the interesterified mixture. Fractionation is preferably done in an organic solvent. The examples of EP 89,082 illustrate spreads comprising margarine fats containing 90 or even 93% sunflower oil and only 7 or 10% hardstock. This hardstock is produced by means of 2 stage fractionation in acetone to obtain a midfraction of a randomly interesterified mixture of 50 parts fully hydrogenated palmkernel fat and 50 parts fully hydrogenated palm fat.
Nowadays there are consumers who express concern about chemically modifying fats e.g. by hydrogenating or hardening, which may result in trans-unsaturation if partial hardening is involved.
To meet the need for spreads with low contents of SAFA in the margarine fat which have been produced without using hydrogenation, CA 2 098 314 proposes to prepare hardstock by chemically interesterifying a blend of generally equal proportions of palm stearin and palmkernel stearin. This hardstock should have the following solid fat contents as measured by AOCS method CD 16-81:
______________________________________ Temp (.degree. C.) % Solids Variance .+-. x ______________________________________ 5 70.49 2% 10 64.45 2% 20 49.83 2% 25 45.66 2% 30 34.13 2% 35 22.17 2% 40 10.90 2% ______________________________________
To obtain the margarine fat for producing the spread 14-21.1%, preferably 14.5-16%, especially about 16% of this hardstock is blended with the balance of vegetable oil, e.g. olive oil, canola oil and/or sunflower oil.
This approach of CA 2 098 314 results in products with higher SAFA contents and lower cis unsaturated fatty acid (UFA) contents, in particular lower all-cis polyunsaturated fatty acid (PUFA) contents than the products described above, because the balance of SAFA and UFA or PUFA is largely determined by the amounts of hardstock and liquid oil in the margarine fat. This would seem to be the inevitable price to pay for not using fully hydrogenated oils. However, this conclusion is undesirable. There is therefore a need for margarine fats that are as good as the prior art products in respect of nutritional properties as well as the sensoric properties of the resulting spreads, but that have been produced without the use of hydrogenation.
We have now found that this objective can be reached to a considerable extent. Accordingly, the invention provides a margarine fatblend essentially comprising 86-95% liquid oil and 5-14% of a hardstock, this hardstock being a stearin fraction of an interesterified mixture of 25-65%, and preferably 35-55%, unhardened lauric fat stearin and 75-35%, and preferably 65-45%, unhardened C.sub.16+ fat stearin. Preferred embodiments of this fatblend are given in claims 2-9. The invention further provides a plastic W/O emulsion spread comprising an aqueous phase and an oil phase predominantly consisting of the present margarine fat blend.
By selecting unhardened natural vegetable fat products having sufficient saturated fatty acids, such as lauric fat fractions and palm oil fractions for the interesterification, the chemical modification of the fats can be reduced to a minimum and the trans fatty acid level in the final fat blend can easily be limited to almost zero.
We were much surprised, however, that with our hardstock produced from unhydrogenated fat we could achieve quite similar results with respect to the nutritional properties of the spread as EP 89,082. EP 89,082 fully concentrates on achieving the minimum SAFA content within the boundaries of sensorically acceptable product properties. To this end it uses the full range of fat modification techniques including hydrogenation, chemical interesterification, solvent fractionation and even chemical synthesis of triglycerides. As will be further elucidated below, we found that with our approach we can even substantially match the performance of EP 89,082 without using solvent fractionation, chemical interesterification, or other chemical modification techniques. Just using the mildest biological and physical techniques of enzymatic interesterification, dry fractionation and blending these results can be obtained.
Furthermore, we found that with our approach compared to the products based on hydrogenated hardstocks as most commonly applied for these low SAFA W/O spreads, products with improved mouthfeel and oral melt can be obtained.
The terms "fat" and "oil" are used in this specification as synonyms. The term "hardstock" refers to fatty acid triglycerides of which at least the majority, preferably at least 90%, of the fatty acids are saturated. Such triglyceride mixtures are solid at ambient temperatures. The hardstock may comprises two or more different hard fats, i.e. it may consist of 2 or more stearin fractions, each being obtained by fractionating an interesterified mixture of 25-65% unhardened lauric fat stearin and 75-35% unhardened C.sub.16+ fat stearin. A "margarine fat" is a fat blend which is suitable for use as the sole fat in plastic w/o spreads or in margarine; such a margarine fat usually includes a hardstock and a liquid oil. The term "liquid oil" is used in this specification for glyceride mixtures that are pourable at 5.degree. C. Preferably the solid fat content of the liquid oil is 0 at 20.degree. C., more preferably it is 0 at 15.degree. C. Solid fats from which lower melting constituents have been removed will be indicated as "stearin fractions". A stearin fraction for the purpose of this description and claims is defined as a triglyceride mixture or fat blend from which at least 10% of the lower melting constituents have been removed by some kind of fractionation, e.g. dry fractionation, multi-stage countercurrent dry fractionation or solvent fractionation.